United Kingdom Atomic Energy Authority

David L Segal

James A Cairns

Edward S Lane

Thomas C Prentice

David C Sammon

This invention relates to aluminium compounds and their preparation. In accordance with the invention a peptizable alumina hydrate is prepared by hydrolyzing an aluminium alkoxide at a water:aluminium ratio at or near the stoichiometric value. One example of an aluminium alkoxide which has been hydrolyzed in accordance with the present invention is aluminium sec-butoxide (Al(OC.sub.4 H.sub.9).sub.3.sup.s); thus alkoxide has been hydrolyzed at water:aluminium ratios of 3:1 and 4:1 to give peptizable alumina hydrates. Cold water (e.g. at 16.degree.-22.degree. C.) and aluminium alkoxide are preferably brought together to effect the hydrolysis.

Process for producing aluminium containing sols

A substrate is provided with a refractory oxide coating by contacting the substrate with a dispersion of a solid particulate phase in a liquid phase, subsequently followed by firing to produce the coating, the dispersion comprising at least a first and a second refractory oxide component. In order to produce a coating of controlled purity, e.g. for certain catalytic, electronic or other appications, the first refractory oxide component (e.g. an alumina) is obtained from a purifiable liquid or solid precursor therefor and constitutes part at least of the solid phase, and the second refractory oxide component is either obtained from a purifiable liquid or solid precursor therefor and constitutes part of the solid phase or is a purifiable liquid precursor (e.g. a water-soluble silicone) constituting part at least of the liquid phase.

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Didcot, United Kingdom

David L Segal